Metabolic dysfunction and diabetes mellitus during long-term follow-up of severe acute pancreatitis: A case-matched study

Endocrine insufficiency following severe acute pancreatitis (SAP) leads to diabetes of the exocrine pancreas, (type 3c diabetes mellitus), however it is not known how this metabolic phenotype differs from that of type 2 diabetes, or how the two subtypes can be differentiated. We sought to determine the prevalence of diabetes following SAP, and to analyse the behaviour of glucose and pancreatic hormones across a 2-h oral glucose tolerance test (OGTT). Twenty-six patients following SAP (mean (range) duration of first SAP episode to study time of 119.3 (14.8–208.9) months) along with 26 matched controls underwent an OGTT with measurement of glucose, insulin, c-peptide, glucagon and pancreatic polypeptide (PP) at fasting/15/90/120min. Beta-cell area was estimated using the 15min c-peptide/glucose ratio, and insulin resistance (IR) using homeostasis model assessment (HOMA) and oral glucose insulin sensitivity (OGIS) models. The prevalence of diabetes/prediabetes was 54% following SAP (38.5% newly-diagnosed compared to 19.2% newly-diagnosed controls). Estimated beta-cell area and IR did not differ between groups. AUC c-peptide was lower in SAP versus controls. AUC insulin and AUC c-peptide were lower in SAP patients with diabetes versus controls with diabetes; between-group differences were observed at the 90 and 120 min time-points only. Half of new diabetes cases in SAP patients were only identified at the 120min timepoint. Diabetes and pre-diabetes occur frequently following SAP and are difficult to distinguish from type 2 diabetes in controls but are characterised by reduced insulin and c-peptide at later stages of an OGTT. Consistent with this observation, most new post SAP diabetes cases were diagnosed by 2-h glucose levels only.